1

Authors:

Ahmad Hakimi bin Mat Nor,

Aklil Hamdee bin Yahuda,

Faizal bin Pakir.

Universiti Tun Hussein Onn Malaysia

2

�Introduction�Problem statement�Objectives�Scope and Limitation�Literature Review�Material and Methods�Result and Disscussions�Conclusion�Recommendation�References

3

�Foundation is an extremely important structure element in every

construction, such as buildings, bridges, dam and roads.

�A foundation is defined as that part of the structure that supports

the weight of the structure and transmits the load to underlying

soil or rock.

�Road construction on the soft soil, such as soft clay, peat, and

organic soil has been considered a tough challenge.

�Failure of soil can be improved using the implementation of

foundation on road.

4

INTRODUCTION

(cont’d)

�The purpose of a foundation is to hold up and hold together the

structure above it.

�That is important to ensure that the foundation is really in a

good condition to avoid the failure of structure or road

construction

�The functions of foundation is to reduce the rate of settlement

of soil.

5

�Road construction on the soil, often being a main problem in

Malaysia. It is because low strength and high compressibility are

typical characteristics of this soil.

�Previous studies proved that the applications of foundation are

relevant to improve the bearing capacity and reduce the rate of

settlement of soil.

�It is called chicken foot foundation method, introduced by

Professor Sediyatmo originated from Indonesia. Chicken foot

foundation also known as “cakar ayam” foundation.

�Usage of this system has been applied in the construction of

roads in Indonesia.

PROBLEM STATEMENT

6

Figure 1 : Failure of rural road

constructed on soft soil at Batu

Pahat, Johor. (AHM Nor et al, 2014)

Parit RasipanParit Karjo

Parit Daun

PROBLEM STATEMENT

(cont’d)

7

� Determine the rate of settlement of lightweight concrete

“cakar ayam” foundation design, on soft clay, clayey silt

and sand, under the different axle load, using Plaxis 3D

foundation software.

� Determine the effectiveness of lightweight concrete “cakar

ayam”foundation design, on soft clay, clayey silt and

sand.

OBJECTIVES OF STUDY

8

SCOPE AND LIMITATION

� The study focuses on the design of lightweight concrete “cakar ayam”

foundation design, on soft clay, clayey silt and sand.

� The soil data and lightweight concrete data is provided from previous

researchers and from plaxis bulletin.

� To achieve the objective of the research, this study is designed and

analyzed using Plaxis 3D foundation software.

9

� Several model of lightweight concrete “cakar ayam” foundation are

designed, with 200 mm thickness of slab, and 1.3m, 1.6 m, 1.9m 2.2

m and 2.5 m length of “cakar ayam” foundation.

� The column size is 0.5 x 0.5 m with the spacing 0.75 m each one.

� Every model is tested by different axle load which is

5kN/m2,10kN/m2,15kN/m2, 20kN/m2, 25kN/m2, 30kN/m2, 35kN/m2

and 40kN/m2.

SCOPE AND LIMITATION

(cont’d)

10

LITERATURE REVIEW

TYPE OF SOIL

� Soil can be divided to three very general categories which are

cohesionless, cohesive and organic soil. Gravel, sand and silt

particles do not tend to stick together, so that they were in

cohesionless categories.

� Whilst, cohesive soils are soil that characterized by very small

particle size and the particles tend to stick to others. Soft soils pose

high moisture content, low shear strength and exhibits high

compressibility.

11

LITERATURE REVIEW

(cont’d)TYPE OF SOIL

� AASTHO system stated that clay particles are less than0.002mm

size while USCS system classified that silt and clay in the same

grain sizes which are less than 0.075mm. Besides that, sand is

classified as a soil that passing 2 mm sieve and retain on 0.075

sieve size based on AASTHO classification system.

� AASTHO also classified that soil criteria based on their plasticity.

When the fine fraction of the soil has a plasticity index of 10 and

less, it is called silty. The term clayey is applied when the fine

fraction have a plasticity index of 11 or more.

12

Figure 2: “Cakar Ayam”

foundation (Tandjiria, 1999)

LITERATURE REVIEW

(cont’d)“CAKAR AYAM” FOUNDATION

13

LITERATURE REVIEW

(cont’d)

� Basic concept of chicken foot foundation is considered as passive

soils that create pressure stiff conditions in the combination of slab and

pipe.

� This means that the thin concrete slab, floating above the ground,

and pipes remain vertical due to passive pressure.

� The foundation was originally proposed to overcome displacement

problems of structures resting on very soft soils(Tandjiria, 1999).

“CAKAR AYAM” FOUNDATION

14

LITERATURE REVIEW

(cont’d)LIGHTWEIGHT CONCRETE

�The properties those are effective with maximum density of about

1760 kg/m3, and a compressive strength of approximately 28 MPa.

The main advantage of using lightweight concrete was it will reduce

dead load.

�According to ACI 212R-03 the Poisson’s ratio of lightweight

concrete value varied between 0.16 and 0.25 with the average being

0.21. A value of 0.20 may be usually assumed for practical design

purposes.

15

METERIAL AND

METHODS

�There are several properties used in plaxis 3D foundation software.

�A few steps have to be done in order to design the foundation using

Plaxis 3D foundation software, which is its general setting, soil

parameter, geometry of model and calculation steps.

�The parameters used in the steps are soil parameter, lightweight

concrete parameter and load distribution value.

�Table 1 shows the properties of soil that were used in Plaxis 3D

foundation software which was obtained from previous researcher

data. Soft clay soil is the soil which was obtained from RECESS,

UTHM. Clayey silt soil data was obtained from Plaxis buletin. While

sand data was obtained from Plaxis 3D foundation manual.

16

METERIAL AND METHODS

(cont’d) Description Symbol Unit Soft clay Sand Clayey silt

0-3.5 m 3.5-10 m

General

Material model Model Hardening soil model

Drainage type Type Undrained Drained Drained

Unit weight above

phreatic levelγ unsat kN/m3 8.190 12.550 17.0 20.000

Unit weight below

phreatic levelγ sat kN/m3 15.075 17.32 20.0 20.200

Parameters

Stiffness

Secant stiffness for CD

triaxial test

(E50ref )

kN/m2 1655.854 2206.588 43000 25000

Tangen odeometer

stiffness

(Eurref )

kN/m2 1324.684 1765.271 43000 25000

Unloading/realoading

stiffness

(Eeodref )

kN/m2 10460.00 5642.000 129000 75000

Power for stress level

dependency of stiffness

M

- 0.85 0.78 0.50 0.80

Strength

Cohesion c’kN/m2 7 10 1 25

Friction angle Φ - 27 30 34 26

Dilatancy angle Ψ - 0 0 4 0

Interfaces

Strength

Interface reduction

factorRinter

-0.5

0.50.7

1.0

Table1:

Hardening

soil model

parameter

17

RESULTS AND DISSCUSSIONS

0.9 0.9 0.9 0.9 0.9

1.3 1.3 1.3 1.3 1.2

1.7 1.7 1.7 1.6 1.6

2.2 2.2 2.1 2.1 2.0

2.7 2.62.6 2.5

2.4

3.23.1

3.02.9

2.8

3.73.6

3.53.4

3.2

4.34.2

4.03.8

3.7

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

1.3 1.6 1.9 2.2 2.5

Set

tlem

ent

(mm

)

Length of Pile (m)

SETTLEMENT VERSUS LENGTH OF PILE

Load 5 kN/m2

Load 10 kN/m2

Load 15 kN/m2

Load 20 kN/m2

Load 25 kN/m2

Load 30 kN/m2

Load 35 kN/m2

Load 40 kN/m2

Figure 3 Graph settlements versus length of pile on clayey silt, with

different distribution load

18

RESULTS AND DISSCUSSIONS

(cont’d)

Figure 4 Graph settlement versus length of pile on sand, with

different distribution load

2.3 2.3 2.2 2.2 2.1

3.4 3.3 3.2 3.1 3.0

4.4 4.34.1 4.0 3.8

5.5 5.35.0 4.9

4.6

6.56.3

6.0 5.85.5

7.57.2

6.96.7

6.3

8.68.2

7.87.5

7.1

9.69.2

8.78.4

8.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

1.3 1.6 1.9 2.2 2.5

Set

tlem

ent

(mm

)

Length of Pile (m)

SETTLEMENT VERSUS LENGTH OF PILE

Load 5 KN/m2

Load 10 KN/m2

Load 15 KN/m2

Load 20 KN/m2

Load 25 KN/m2

Load 30 KN/m2

Load 35 KN/m2

Load 40 KN/m2

19

RESULTS AND DISSCUSSIONS

(cont’d)

Figure 5 Graph settlement versus length of pile on softclay, with

different distribution load

11.7 11.9 12.1 12.3 12.3

17.8 17.9 17.9 18.0 17.8

24.6 24.4 24.3 24.2 23.6

32.2 31.6 31.2 30.8 29.9

40.7 39.6 38.8 38.0 36.6

50.748.5 47.0 45.8

43.9

62.658.8

56.254.1

51.5

77.3

70.9

66.563.3

59.8

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

1.3 1.6 1.9 2.2 2.5

Set

tlem

ent

(mm

)

Length of Pile (m)

SETTLEMENT VERSUS LENGTH OF PILE

Load 5 KN/m2

Load 10 KN/m2

Load 15 KN/m2

Load 20 KN/m2

Load 25 KN/m2

Load 30 KN/m2

Load 35 KN/m2

Load 40 KN/m2

20

RESULTS AND DISSCUSSIONS

(cont’d)

�The figure 3 it is shown that the foundation on soft clay can only be

acceptable when load of 5KN/m2, 10 KN/m2, and 15 KN/m2 were

applied. Started from the load of 20 KN/m2, the value of settlement

exceeded the limit which is 25 mm. So that the foundation concept is

not suitable to be applied on soft clay soil.

�This is due to the properties of soil that are not suitable to apply this

concept. Having been discussed that, soft soils posed high moisture

content, low shear strength and exhibits high compressibility.

�The figure 4, it can be seen that the value of settlement on

foundation is acceptable when loads were applied on sand. The

value of settlement decreased when lengths of pile increased.

Therefore, the foundation concept is suitable to be applied on sand.

21

RESULTS AND DISSCUSSIONS

(cont’d)

� Properties of the sand support the implementation of the “cakar

ayam” foundation concept. It would help in reducing the value of the

settlement. The value of cohesion of the sand is low, but its value of

friction is high. The value of friction of the sand will help to increase the

strength of the soil. It can be seen based on the formula of shear

strength parameter in terms of effective stress. Sand stiffness

parameter is high which will help to reduce the value of the settlement.

This is due to the stiffness values which also depends on the effective

stress value of the sand. Rotation of the pipe columns will be counter

back by the lateral earth pressure, that are acting around the pipe

columns. So that passive pressure will help to reduce the settlement

value.

22

RESULTS AND DISSCUSSIONS

(cont’d)

� From the figure, it can be seen that the value of settlement on

the foundation is acceptable when loads were applied on clayey silt.

The value of settlement decreased when lengths of pile increased.

So that the foundation concept is suitable to be applied on clayey

silt.

� The properties of clayey silt would help the implementation

of the “cakar ayam” foundation concept. It will help to reduce the

value of the settlement. The value of cohesion and friction of soil is

high. This will help to increase the strength of the soil. It can be seen

based on the formula of shear strength parameter in terms of

effective stress.

23

� Furthermore, clayey silt stiffness parameter is high which

could help in reducing the value of the settlement. Deflection that

occurs on the concrete slab of “cakar ayam” foundation will cause

the pipe columns to rotate about its axis. Rotation of the pipe

columns will be counter back by the lateral earth pressure, that are

acting around the pipe columns. So that passive pressure will help

to reduce the settlement value.

� Overall, the value of the settlement also is rather low due to

the unit weight of lightweight concrete which will reduce the value

of the settlement results. It would make the settlement value more

safe.

RESULTS AND DISSCUSSIONS

(cont’d)

24

CONCLUSION

�The results show that the lightweight “cakar ayam” foundation

concept was suitable to be implemented on sand and clayey silt

soils. This is because of all the value obtained from Plaxis 3D

foundation software are acceptable, which is under the safe

limit, 25 mm.

�The trends of the settlement also show that when the lengths

of “cakar ayam” foundation increase, the values of settlement

decrease.

�Besides that, this concept is still not suitable to be

implemented on soft clay soil. This is because the results show

that the settlement value obtained from Plaxis 3D foundation

software, are still over the limit.

25

CONCLUSION

(cont’d)

�The results also show that the value of settlement was

relatively low. This is affected from the implementation of

lightweight concrete “cakar ayam” foundation.

�The unit weight of concrete is low. This will reduce the

selfweight of foundation and the value of the settlement.

Nevertheless, the research was addressing their objective.

26

Recommendation

�Studies of “cakar ayam” foundation concept can be implemented

on others soil type, using Plaxis 3D foundation software.

�Studies also need to get the detailed information properties of

soil on the site, during the project implementation. This is because

usually in road construction, soil compacted that will causes of soil

properties change. While this method is not conducted and

analysis in Plaxis 3D foundation software.

�Determine the way how to overcome the “cakar ayam”

foundation problem on soft such as soft clay soil.If “cakar ayam”

foundation still not suitable for implementation in soft clay soil, the

soil must be stabilized first, before the implementation of “cakar

ayam” foundation concept.

27

REFERENCES

Frederick S. Merritt, J. T. (2001). Section Six: Soil Mechanics and

Foundation . In R. W. Day, Building and Construction Handbook (p. 6.2).

Washinton D.C: McGRAW-HILl.

AHM Nor et al. (2014). Site Investigation Of Road Drains For Rural Road On

BatuPahat Soft Clay (BPSC),International Organization of Scientific

Research (IOSR) 11 (2), Ver. VIII, PP 12-19.

Pakir, F. Bin, Abdul Karim, A. T. Bin, Ling, F. N. L., & Kassim, K. A. (2013).

Effect of Humic Acid on Geochemistry Properties of Kaolin. Advanced

Materials Research, 701, 310–313.

doi:10.4028/www.scientific.net/AMR.701.310

Mat Nor, A. H. (2012). Performance of Unpaved Road with Different Soft

Clay Reinforcement. Malaysia: Master’s Thesis. Faculty of Civil and

Environmental Engineering, Universiti Tun Hussein Onn.

Dr. Wout Broere, D. R. (17/ March 2005). Plaxis Buletin, Control of Ground

Movement.

28

Brinkgreve, R. B. (2012). Plaxis 3D 2012. Netherland: Plaxis Bv.

Kamon M, .. B. (1992). Ground Improvement Techniques . Proc. of the 9th

Asian Regional Conf. on Soil Mech. and Found. Engineering, Vol. 2, (pp.

526-546). Bangkok.

Craig, R. F. (2006). Craig.s Soil Mechanic. Canada: Spoon Press.

Vipman, T. (1999). Numerical Modelling of Chicken-Foot Foundation. Petra

CristianUniversity

Short. A, K. W. (1978). Light Weight Concrete 3rd Edition. England: Apply

Science Publisher.

REFERENCES

(cont’d)

End of Presentation29